Sh 2-184
Coordinates: (123.1°, -6.3°)
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Often called NGC 281, this bright nebula located far below the galactic plane is also nicknamed the Pac Man nebula by amateur astronomers after a 1980s-era video game character.
IC 1590, the star cluster at the heart of the nebula, is about 3.5 million years old. The core of the star cluster IC 1590 is the trapezium system HD 5005, which ionises NGC 281 and contains an O5.5 class star.
The distance to NGC 281 has been accurately measured via radio parallax as 2820 +/- 240 pc.
It is highly unusual to find such a prominent nebula so far below the galactic plane and there is some evidence that it is on the edge of a superbubble that has blown out of the galactic plane, perhaps because of multiple supernova explosions.
This nebula is often the subject of astrophotographers and there are many beautiful images of it on the Internet. One interesting false-colour version was Astronomy Picture of the Day.
You can see a view of this nebula in infrared taken by the WISE satellite here.
IC 1590, the star cluster at the heart of the nebula, is about 3.5 million years old. The core of the star cluster IC 1590 is the trapezium system HD 5005, which ionises NGC 281 and contains an O5.5 class star.
The distance to NGC 281 has been accurately measured via radio parallax as 2820 +/- 240 pc.
It is highly unusual to find such a prominent nebula so far below the galactic plane and there is some evidence that it is on the edge of a superbubble that has blown out of the galactic plane, perhaps because of multiple supernova explosions.
This nebula is often the subject of astrophotographers and there are many beautiful images of it on the Internet. One interesting false-colour version was Astronomy Picture of the Day.
You can see a view of this nebula in infrared taken by the WISE satellite here.
The core of the star cluster IC 1590 is the trapezium system HD 5005, which ionises the nebula.[1]
Recent study. [2]
Evidence of superbubble blowout. [3]
IC 1590, the star cluster at the heart of the nebula, is about 3.5 million years old. [4]
Recent study. [2]
Evidence of superbubble blowout. [3]
IC 1590, the star cluster at the heart of the nebula, is about 3.5 million years old. [4]
Notes
1. ^ Henning, Th., Martin, K., Reimann, H.-G., et al. (1994). "Multi-wavelength study of NGC 281 A", Astronomy and Astrophysics, Vol. 288, 282-292. [1994A&A...288..282H]
2. ^ Lee, Youngung & Jung, Jae-Hoon (2003). "A molecular cloud complex above the galactic plane.. I. Extended CO observations of the NGC 281 region", New Astronomy, Vol. 8, 191-207. [2003NewA....8..191L]
3. ^ Sato, Mayumi, Hirota, Tomoya, Honma, Mareki, et al. (2007). "Absolute Proper Motions of H2OMasers Away from the Galactic Plane Measured with VERA in the "Superbubble" Region NGC 281", Publications of the Astronomical Society of Japan, Vol. 59, 743. [2007PASJ...59..743S]
4. ^ Guetter, Harry H. & Turner, David G. (1997). "IC 1590, A Young Cluster Embedded in the Nebulosity of NGC 281", The Astronomical Journal, Vol. 113, 2116. [1997AJ....113.2116G]
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Most of the sources used to create these nebula descriptions are listed in the
notes section for each description. In some cases,
for example the Avedisova, Humphreys and Reed catalogs, the source is used extensively and is not listed in the
individual nebula descriptions. See this catalog overview
for more information on the catalogs and the general sources used
to create these descriptions and this introduction to HII regions
on the general history of this area of astronomy.
This image was created using the POSS-II/UKSTU data of the Digitized Sky Survey and SuperCOSMOS using the process described here.
According to my correspondence with the Royal Observatory Edinburgh and the Space Telescope Science Institute, I am allowed to use the POSS-II/UKSTU data to create and display images for non-commercial purposes so long as I include this fine print for the SuperCOSMOS data:
Use of these images is courtesy of the UK Schmidt Telescope (copyright in which is owned by the Particle Physics and Astronomy Research Council of the UK and the Anglo-Australian Telescope Board) and the Southern Sky Survey as created by the SuperCOSMOS measuring machine and are reproduced here with permission from the Royal Observatory Edinburgh.
and this acknowledgement taken from the DSS site:
The Digitized Sky Surveys were produced at the Space Telescope Science Institute under U.S. Government grant NAG W-2166. The images of these surveys are based on photographic data obtained using the Oschin Schmidt Telescope on Palomar Mountain and the UK Schmidt Telescope. The plates were processed into the present compressed digital form with the permission of these institutions.
The Second Palomar Observatory Sky Survey (POSS-II) was made by the California Institute of Technology with funds from the National Science Foundation, the National Geographic Society, the Sloan Foundation, the Samuel Oschin Foundation, and the Eastman Kodak Corporation.
The UK Schmidt Telescope was operated by the Royal Observatory Edinburgh, with funding from the UK Science and Engineering Research Council (later the UK Particle Physics and Astronomy Research Council), until 1988 June, and thereafter by the Anglo-Australian Observatory. The blue plates of the southern Sky Atlas and its Equatorial Extension (together known as the SERC-J), as well as the Equatorial Red (ER), and the Second Epoch [red] Survey (SES) were all taken with the UK Schmidt.
The "Second Epoch Survey" of the southern sky was made by the Anglo-Australian Observatory (AAO) with the UK Schmidt Telescope. Plates from this survey have been digitized and compressed by the ST ScI. The digitized images are copyright ? 1993-5 by the Anglo-Australian Observatory Board, and are distributed herein by agreement.
The "Equatorial Red Atlas" of the southern sky was made with the UK Schmidt Telescope. Plates from this survey have been digitized and compressed by the ST ScI. The digitized images are copyright ? 1992-5, jointly by the UK SERC/PPARC (Particle Physics and Astronomy Research Council, formerly Science and Engineering Research Council) and the Anglo-Australian Telescope Board, and are distributed herein by agreement.
The compressed files of the "Palomar Observatory - Space Telescope Science Institute Digital Sky Survey" of the northern sky, based on scans of the Second Palomar Sky Survey are copyright ? 1993-1995 by the California Institute of Technology and are distributed herein by agreement. The compressed files of the "Palomar Observatory - Space Telescope Science Institute Digital Sky Survey" of the northern sky, based on scans of the Second Palomar Sky Survey are copyright ? 1993-1995 by the California Institute of Technology and are distributed herein by agreement.